Cartridge-operated tools



.5 Sheets-Sheet 1 Inventor army; 4

J. E. JEPHSON CARTRIDGE-OPERATED TOOLS NM 6 mm 0 9w Q m g m3. v

Oct. 21, 1969 Filed Sept. 12, 1966 1969; J. E. JEPHSON 3,47

CARTRIDGE-OPERATED TOOLS Filed Sept. 12, 1966 .5 Sheets-Sheet 2 lrwenlor J. E. J'EPusou uilww Attorneys Oct. 1969 J. E. JEPHSON CARTRIDGE-OPERATED TOOLS .5 Sheets- -Sheet 5 Filed Sept. 12. 1966 f a l n e o n 1 IE. .TE'PasOu B A ltorneys Oct. 21, 1969 J. E. JEPHSON 3,473,719

CARTRIDGE-OPERATED TOOLS Filed Sept. 12, 1966 .5 Sheets-Sheet 4 9 75 24 30 31 47 5ab 4o Inventor I E. .TsPusml A ilorneyg Oct. 21, 1969 w J. E. JEPHSON 3,473,719

CARTRIDGE-OPERATED TOOLS Filed Sept. 12. 1966 5 Sheets-Sheet 5 Inventor IE TE'PHSON By S M M to Attorneys:

3,473,719 CARTRIDGE-OPERATED TGOLS John Edward .Iephson, Greenford, England, assignor, by mesne assignments, to Sterling Engineering Company Limited Filed Sept. 12, 1966, Ser. No. 578,809 Int. Cl. B25c 1/18 11.5. Cl. 22711 19 Claims ABSTRACT OF THE DISCLOSURE This invention relates to a semi-automatic cartridgeoperated hand tool for firing fasteners into structures, employing an elongated magazine, provided with a row of cartridgeand fastener-receiving chambers, which is adapted to be bodily advanced, step-by-step, transversely through the tool, upon longitudinal displacement of an internal operating mechanism which is actuated by pressing the tool against a structure, thereby to bring successive cartridge chambers into an operative or firing position aligned with the barrel.

The present invention relates to cartridge-operated hand tools for firing fasteners such as rivets, pins, bolts, or other projectiles, into the surfaces of Walls or other structures. More particularly, the invention relates to a tool of this type which is so constructed that it may only be fired when the muzzle of the tool barrel is pressed against a surface.

The present invention consists in a cartridge-operated hand tool of the aforementioned type, which includes a tool housing, a barrel mounted in the housing operating means movable from a first position, to a second position in which the tool is conditioned for firing, by urging the muzzle of the tool against a surface, and an opening in the housing to accommodate an elongated magazine provided with a row of cartridge chambers, the operating means being co-operable with the magazine upon movement of said means between said first and second positions to bodily advance the magazine through the housing generally transversely of the barrel in a step-Wise manner.

In one embodiment of the invention, the barrel is slidable telescopically relative to the tool housing, and is normally resiliently urged towards its fully extended position. By pressing the muzzle of the tool firmly against a surface, the barrel is retracted into the housing, the retracting movement of the latter serving to advance the magazine bodily step-wise, transversely through the tool, to bring successive loading cartridge chambers into line with the bore of the barrel and a firing pin associated with the firing mechanism.

The advance of the magazine, which may be oblong in shape, is effected by operating means comprising, for example, pawls movable axially with the barrel and cooperable with corresponding surfaces of the magazine.

In order that the invention may be more readily understood, one embodiment of a cartridge-operated hand tool according to the present invention will now be described with reference to the accompanying drawings, in which:

FIGURE 1 is a longitudinal section of the tool in its normal condition with the barrel fully extended relative to the housing;

FIGURE 2 is a partial horizontal section on the line AA of FIGURE 1 with the magazine unsectioned;

FIGURE 3 is a longitudinal section of the tool shown in FIGURE 1, but conditioned for firing with the barrel fully retracted;

FIGURE 4 is a partial horizontal section on the line B-B of FIGURE 3 with the magazine unsectioned, and

FIGURE 5 is an exploded perspective view of the nited States Patent 0 "ice barrel, firing pin block and magazine, shown in the preceding figures.

Referring to the drawings, the hand tool comprises a housing formed in two parts, for example as light alloy castings. A rear housing part 1 forms the stock of the tool which is provided with a hand-grip 2 and contains a firing mechanism 3. The part 1 is detachably secured by co-operating screw threads 4 and set screws 5 to a tubular forward housing part 6 containing an axially slidable barrel 7. The two housing parts 1 and 6, in the region between the firing mechanism 3 and the rearward end of the barrel 7 are formed with two slots (not shown), one in each side of the tool, which define a transverse passage to receive and locate an elongated, generally rectangular, magazine 8, so as to permit the magazine to slide bodily transversely through the housing during operation of the tool.

Referring particularly to FIGURES 1 and 5, the barrel 7 has two bores 9, each provided, adjacent the muzzle of the barrel, with gas vents or ports 10. Surrounding the muzzle is a splinter or flash guard 11 which forms an extension of an axially slidable sleeve 12 which extends between the barrel and housing part 6. The sleeve 12 is retained on the barrel 7 by a ring 13 screwed onto the muzzle of the barrel, the sleeve 12 is normally urged into engagement with the ring 13 'by a compression spring 14- located between the sleeve 12 and a shoulder 15 formed Within the housing part 6. This spring 14, via the sleeve 12 and ring 13 normally urges the barrel 7 into the fully extended position shown in FIGURE 1, in which a cylindrical enlargement 16 at the rearward end of the barrel 9 abuts the shoulder 15.

Integral with and extending rearwardly from the cylindrical enlargement 16 towards the firing mechanism 3 are upper and lower arms 17 and 18, which are spaced apart vertically to accommodate the magazine 8 for bodily transverse sliding movement of the latter. The arm 17, on its fiat downwardly facing surface adjacent the enlargement 16, carries a generally axially rearwardly extending finger or pawl 19 which is rockable about a pivot pin 20 by a limited amount determined by a second pin 21 which extends into an aperture 22 in the pawl 19 which is slightly larger than the head of the pin 21. The upwardly facing surface of the lower arm 18 carries a pawl 23 in the form of a fixed pin or boss. The two pawls 19 and 23 constitute the operating means for advancing the magazine 8 through the tool in a stepwise manner as will be described later.

The arms 17 and 18 also serve to transmit axial movement of the barrel 7 to the firing mechanism 3 to cock the latter. This firing mechanism includes a firing pin block or breech block 24, shaped as shown in FIGURE 5, and having a fiat forward face 25 engageable with the rearward face 26 of the magazine 8, provided with two firing pinapertures 27. The block 24 includes horizontally extending upper and lower faces 28 which are located between and engage the arms 17 and 18. At least the lower face 28 is recessed at 29 to provide a clearance for the lower pawl 23 when the barrel 7, and therefore the arms 17 and 18 slide rearwardly relative to the breech block 24. The block 24 also includes a pair of arcuate lateral shoulders 30 which locate in correspondingly shaped axially extending channels 31 (FIGURES 2 and 4) in the housing part 1. The breech block 24 is thus axially slidable but not rotatable relative to the part 1, and since the arms 17 and 18 of the barrel engage with the faces 28 of the block, the barrel is also prevented from rotating or rocking within the housing part 1. The amount of axial movement of the breech block 24 is limited by integral ring segments 32 (FIGURE 5) which engage in recesses 33 in the housing part 1 (FIGURES 1 and 3).

A cavity 34 is provided in the rear face of the breech block 24, including two conical recesses 35, the apices of which comprise the firing pin apertures 27. A correspondingly shaped firing pin 36 is free to float axially in the cavity 34, and has apair of conical cartridge-engaging projections 36a which are so dimensioned that their tips project through the two firing pin apertures 27 when the pin 36 is in its most forward position.

The breech block 24 is normally resiliently urged towards the muzzle of the tool by two transversely spaced compression springs 37 (FIGURES 2 and 4) mounted in longitudinally extending passages in the housing part 1, these springs engaging between the rear surfaces of the shoulders 30 of the breech block and a hammer block 38. This hammer-block, which, together with its associated components, also forms part of the firing mechanism 3, is detachably secured in the housing part 1 by set screws 39.

The hammer block 38 comprises a first cylindrical part 38a by means of which the block 38 is accurately located in the housing part 1, and a reduced diameter, forwardly extending, cylindrical part 38b. A passage 40 extends in an axial direction through the block 38, and slidably mounted in this passage 40 is a firing pin hammer 41, normally resiliently urged towards the breech block 24, to a position in which a shoulder 42 on the hammer 41 abuts a ring 43 screwed into the mouth of the passage 40, by a hammer spring 44 acting between the shoulder 42 and a step 40a in the passage 40. The cylindrical parts 38a and 38b are cut away rearwardly of the step 40a to form a slot 45 communicating with the passage 40, which slot, where it extends through the part 38a has an inclined roof 46. Slidable axially on the part 38b of the hammer block is a tubular firing pin block 47, which is normally resiliently urged into engagement with the rear face of the breech block 24 (FIGURES l and 2) by a spring 48. The firing pin block 47 has at its forward end an annular shoulder 49 which is en-gageable by the rearward end of the arms 17 and 18 when the barrel is retracted to the position shown in FIGURES 3 and 4. A leaf-spring 50 is secured to the firing pin block 47 and extends rearwardly therefrom. The rearward end of this leaf-spring 50 is folded over into a turned-up portion 51, and adjacent this portion 51 is a scar 52 in the form of a rivet having an inclined end, the sear being normally urged by the leaf-spring through the slot 45 into engagement with the firing pin hammer 41 adjacent a step 53.

Projecting from the rear face of the hammer block 38 is a pair of arms 54 between which are pivotally mounted a pair of interengaging levers 55 and 56, rockable about pivot pins 57 and 58 respectively. The lower lever 56 is slotted at 59, and within this slot 59 is located a recessed portion of a rod 60 slidable in a passage in the stock of the housing part 1, and biassed to the position shown in FIGURES l and 3 by a compression spring 61. The rod 60 at its end remote from the lever 56, carries a trigger 62. The levers 56 and 57, and the rear of the firing mechanism 3, are enclosed in a detachable end cap 63, formed, for example, as an alloy casting and held in place by screws 64.

The magazine 8, which is separate from the tool, comprises a rectangular elongated block which may be made from a light alloy, from a synthetic plastic material, or perspex. This magazine is provided with two tiers or rows of cartridge chambers 65, each chamber being dimensioned to receive a cartridge and fastener (not shown), and each row, when the magazine is inserted into the tool, being in vertical alignment with one of the bores 9 in the barrel 7. The chambers 65 of one row are vertically offset or staggered relative to the chambers of the other row as is clearly seen in FIGURE 5, and the rear face 26 of the magazine is formed with a transverse groove 66 in line with each row to preventthe apices of the portions 36a of the firing pin from engaging the magazine between the chambers 65. As will also be seen from FIGURE 5,

the upper surface of the magazine is provided with a plurality of forwardly opening recesses 67 spaced from the forward edge of the magazine 8 by a relieved portion 68 and defining between them axially extending teeth 69 having inclined leading edges 70. The teeth 69 are spaced from the right hand end of the magazine as viewed in FIGURE 5, by a relieved portion 71.

As shown in FIGURES 2 and 4, in broken lines, the lower surface of the magazine is also provided with a plurality of recesses 72 defined by teeth 73 having inclined leading edges 74. These recesses 72, however, open rearwardly and are disposed directly adjacent the rearward edge of the magazine. The teeth 73 are spaced from the left hand end of the magazine as viewed in FIG- URES 2 and 4 by a relieved portion 75, similar to the relieved portion 71 in the upper surface. The recesses 67 and 72 in the upper and lower surfaces of the magazine are dimensioned to slidably receive the pawls 19 and 23 respectively, with a minimum of lateral play between the pawls and their associated recesses.

The two slots (not shown) in opposite sides of the tool housing, through which the magazine slides, are shaped and dimensioned to correspond to the outline of the magazine, so that the magazine can only be inserted into the tool the right way up, and with the cartridge chambers 65 facing in the correct direction. The axial dimensions of said slots, however, are such that the magazine is able to move back and forth bodily axially by a small amount.

In operation, the magazine 8 is first loaded with a cartridge and a fastener, e.g., a rivet (not shown) in each of its chambers 65, and is then inserted into the tool transversely from right to left as viewed in FIG- URE 2, i.e., with the end of the magazine having the relieved portion 75 leading, and with the barrel of the tool in its normal, extended position (see also FIGURE 1). As the magazine'is inserted, the breech-block 24 is displaced rearwardly by a small distance, against the action of the springs 37 and 48, and in order to facilitate initial displacement of the breech block 24 as the magazine is inserted, the leading portion of the magazine may be slightly tapered. Insertion of the magazine is halted when the first lower tooth 74 thereof, which is adjacent the relieved portion 75 butts against the side of the lower pawl 23. The tool is now ready for operation, and its components are in the position shown in FIGURES 1 and 2, namely the barrel 7 and sleeve 12 are urged by the spring 14 to their fully extended position, in which the rearward ends of the bores 9 in the barrel 7 are spaced from the forward face of the magazine 8, and the upper pawl 19 is axially spaced from recesses 67 in the upper surface of the magazine. In this condition, the magazine is pressed resiliently against the forward end of the slot (not shown) in the housing by the breech block 24 and the firing pin apertures 27 are not in alignment with the cartridge chambers 65 in either row, so that even if the firing pin 38 were to be accidentally actuated, the apices of the firing pin would not contact the percussion cap of a cartridge but would enter the grooves 66 between the chambers, so that accidental firing of the tool is avoided. The firing pin block resiliently engages the breech block 24, the sear 52 carried by the leaf-spring 50 engages behind the step 53 in the hammer 41, and the turned up portion 51 of the leaf-spring is disposed beneath the inclined roof 46 in the part 38a of the hammer block. The hammer 41 is in its fully forward position.

To condition the tool for firing, it is pressed against the surface which is to be riveted with a :force sufiicient to overcome the combined forces exerted by the springs 14, 44 and 48. Such pressure telescopes the sleeve 12 and barrel 7 bodily relative to the housing part 6, and as a comparison of FIGURES 2 and 4 will show, this action moves the lower pawl 23 axially out of engagement with the first lower tooth 73, whereafter the upper pawl 19 engages the inclined leading edge 70 of the first upper tooth 69, deflecting this tooth and therefore the magazine bodily transversely step-wise until the first upper recess 67 is in alignment with the pawl 19, and the latter is engaged in this recess, preventing any further transverse movement of the magazine. Before the rear of the splinter guard 11 engages the forward edge of the housing part 6, the rear end of the barrel 7 engages the forward face of the magazine and the magazine together with the breech block is urged rearwards by a small distance thereby to ensure that the magazine is firmly engaged by both the barrel 7 and the breech block 24. The step-wise advance of the magazine 8 brings the cartridge in the first chamber 65 in the upper row into alignment with the upper firing pin aperture 27, whilst the lower aperture 27 and the first lower chamber 65 are still out of alignment.

Cocking of the firing mechanism 3 as the barrel is retracted is effected by the arms 17 and 18, which engage the firing pin block 47 and urge it, together with the leaf spring 50, sear 52 and hammer 41 rearwardly against the action of the springs 44 and 48 as shown in FIGURES 3 and 4, until, in the fully retracted position of the barrel, the turned-up portion 51 of the leaf-spring is positioned wholly rearwardly of the inclined roof 46, and above a finger 55a of the upper lever 55. If the trigger 62 is now pressed, the upper lever 55 is rocked clockwise via the rod 60 and lower lever 56, and the finger 55a engages beneath the turned-up portion 51 of the leaf-spring and lifts the sear 52 out of engagement with the step 53 in the hammer 41. The hammer is then impelled forward by its spring 44 and strikes the firing pin, impelling the firing pin forward so that the apices of its conical portions emerge through the firing pin apertures 27 and the apex of the upper projection strikes and detonates the cartridge in the first upper chamber. The associated fastener is fired down the barrel, and penetrates the surface of the structure against which the muzzle of the tool is pressed. When the fastener has passed the vents or ports 10, the compressed gases in the barrel produced by the detonation are free to pass out of these port into the space between the barrel and the sleeve 12, and dissipate, thus substantially reducing recoil or kick of the tool, which would otherwise be transmitted to the operator.

If the barrel 7 is not completely retracted to the position shown in FIGURES 3 and 4, which may occur if the muzzle is not pressed with sufiicient force against the surface, or if the barrel is not held with its bores at right angles to the surface, the firing pin block 49 and leafspring 59 will consequently not be fully retracted, and the turned-up portion 51 of the leaf-spring will be positioned beneath the inclined roof 46. In this position, although the finger 55a of the upper lever 55 will engage beneath the turned-up portion 51 if the trigger 62 is pressed, the portion 51 engages the roof 46 and cannot be raised to disengage the sear 52 from the step 53 on the hammer 41. It is thus virtually impossible to release the hammer.

After firing, the tool is withdrawn from the surface and the barrel and splinter guard are spring urged to their FIGURES 1 and 2 position. This movement causes the upper pawl 19 to be withdrawn axially from the first upper recess 67 and the lower pawl 23 to engage the inclined leading edge 74 of the first lower tooth 73, deflecting this tooth, and therefore the magazine bodily step-wise in the direction of the arrow in FIGURE 2. The lower pawl enters the first lower recess 72, and locates the magazine in a position in which the cartridge chambers 65 in both rows are out of alignment with the firing pin apertures 27.

The extending movement of the barrel also permits the firing pin block 47 to return under spring pressure to its FIGURES 1 and 2 position, during which movement the sear 52 rides up over the rear of the hammer 41 and snaps in front of the step 53.

When the tool is again pressed against a surface the same step-wise transverse advance movement of the magazine occurs, i.e. the lower pawl 23 disengages axially from the first lower recess 72, the upper pawl 19 then engages the inclined leading edge of the second upper tooth, and the magazine is deflected transversely in a step-wise manner in the direction of the arrow until the pawl 19 enters the next upper recess 67. The retraction of the barrel also re-cocks the firing mechanism 3. In this position the first cartridge chamber in the lower row is aligned with the lower bore 9 of the barrel and with the lower firing pin aperture 27, so that firing of the tool detonates the cartridge in that chamber, but no other. Subsequent withdrawal of the tool from the surface steps the magazine forward as previously described.

It will thus be seen that the magazine is bodily advanced through the tool, transversely of the barrel by one step, equal to one half of the transverse distance between any chamber in one row and its adjacent chamber in the other row every time the barrel is retracted, to bring a cartridge chamber first in one row and then in the other row into a firing position. Every time the tool is with drawn from the surface and the barrel extended, the magazine is also advanced transversely by the same size step, to a position in which the cartridge chambers in both rows are out of alignment with the firing pin apertures.

When all of the cartridges have been fired (24 in the embodiment illustrated), and the upper pawl 19 is engaged in the upper relieved portion 71, no further advance movement of the magazine takes place upon axial movement of the barrel, and the magazine 8 may be manually extracted and either reloaded or replaced by a further loaded magazine.

By permitting a small rocking movement of the upper pawl 19, any tendency for this pawl to jam or wedge against the leading edges of the upper teeth 69 is reduced or eliminated. Since the pawl 19 is comparatively deep axially and a close fit within the upper recesses 67, once the pawl has engaged within a recess, no rocking movement of the pawl, or consequential transverse play of the magazine which would result in mis-alignment of the bores 9 with the chambers 65 is possible, when the tool is conditioned for firing.

In order to facilitate extraction of the magazine before all of the cartridges have been detonated, without having to pump the tool to advance the magazine, or in order to insert the magazine to any desired transverse position in the tool, the axial spacing between the upper and lower pawls 19, 23 is made greater than the axial spacing between the leading edges 70, 74 of the upper and lower teeth of the magazine. With this arrangement, the barrel may be partially retracted to a position in which both the upper and lower pawls are disengaged from their respective teeth, thereby permitting extraction or insertion of the magazine.

It will be understood that various modifications may be made without departing from the scope of the present invention. For example, although in the embodiment described, the magazine accommodates 24 cartridges and fasteners in two rows or tiers of 12, the tool and magazine may be designed to accommodate any number of cartridges and fasteners arranged in a single row of chambers, or in more than two rows, the barrel being provided with a corresponding number of bores and the firing pin being provided with a corresponding number of cartridge engaging projections. It is also possible by suitable design of the magazine to use a single tier magazine with the twin bore tool illustrated in the drawings.

The firing pin hammer 41 may be coaxial with the firing pin 36, instead of offset, and with modification of the associated firing mechanism, the trigger may be coupled to the mechanism via a single lever instead of two levers 55 and 56. Moreover instead of employing a firing pin provided with two conical projections as shown, the firing pin may have differently shaped cartridge engaging portions. For example, the conical portions may be replaced by a single forwardly facing tubular portion having a sharpened leading edge which is engageable with the percussion caps of the cartridges, or with the rims thereof in the case of rim detonated cartridges.

When the tool is designed for use with a single tier magazine, accurate location of, and the gas seal between, the cartridge chambers and the bore in the barrel may be facilitated by providing a recess, for example a conical or tapered recess at the rearward end of the bore, which is co-opera-ble with a conical extension of each cartridge chamber of the magazine, when the barrel is retracted.

If desired, the breech block 24 may be immobile within the housing part 11 instead of being resiliently mounted. Moreover, the splinter guard may be secured directly to the forward end of the housing part 6, in which event the sleeve 12 may be omitted. The splinter guard may be modified to receive and locate elements such as angle brackets, conduit clips, cleats or the like which are to be fastened to a surface so that the elements, and in particular, mounting apertures in the elements, are accurately aligned with the barrel of the tool. In this respect the splinter guard, or a number of readily interchangeable guards, may be provided with resilient or magnetic jaws or chucks, or may be shaped or dimensioned, or provided Witth cut-outs to index the elements.

The upper pawl 19 may be fixed instead of rockably mounted, and may comprise a pin or stud similar to the lower pawl 23. Alternatively, the lower pawl may be rockably mounted instead of, or in addition to, the upper pawl.

I claim:

1. A cartridge-operated hand tool of the type specified which includes a housing having an opening or recess therein to accommodate an elongated magazine provided with a row of cartridge chambers and with indexing surfaces, a barrel mounted in the housing and movable longitudinally of the housing from an extended position, to a retracted position in which the tool is conditioned for firing, by urging the muzzle of the tool against a surface, and operating means mounted within the housing and longitudinally displaceable relative thereto, said means comprising first and second operating members which, when a magazine is operative assembled to the tool and the barrel is displaced between its extended and retracted positions, are longitudinally displaced whilst co-operating with the indexing surfaces of the magazine to effect bodily advancement of the magazine through the housing generally transversely of the barrel in a step-wise manner.

2. A tool as claimed in claim 1, wherein the magazine comprises a generally rectangular elongated member provided with a row of cartridge-receiving chambers, the axes of which are disposed in a common transverse plane, and the indexing surfaces consist of the side walls of a plurality of generally longitudinally extending open ended indexing slots arranged in two transversely extending rows, the slots in one row opening in a longitudinal direction opposite to that of the slots in the other row.

3. A tool as claimed in claim 2, wherein the magazine is bounded by first and second transversely extending mutually spaced faces disposed in planes generally parallel to, and on opposite sides of, said common plane, said first and second rows of slots being carried by said first and second faces respectively, and the slots in each being fiatbottomed.

4. A tool as claimed in claim 3, wherein the barrel is slidable telescopically longitudinally relative to the tool housing, and is normaly resiliently urged towards its full extended position, and wherein the first operating member is carried by a first arm connected to the barrel at its end remote from the muzzle of the tool and disposed adjacent one of said faces of an operatively asembled magazine, so as to be movable bodily longitudinally with the barrel, whereby sliding movement of the barrel relative to the housing eifects advancement of the magazine bodily stepwise, transversely through the tool.

5. A tool as claimed in claim 4, wherein the first arm is one of a pair of arms connected to the barrel and adapted to slidably embrace an operatively assembled magazine. said first operating member comprising a first pawl co operable with the first of the two rows of indexing surfaces of the magazine to bodily advance the magazine during retraction of the barrel relative to the housing, the barrel being movable to a position in which the first pawl is separated from the first row of indexing surfaces, enabling the magazine to be bodily moved transversely through the tool independently of the operating means.

6. A cartridge-operated hand tool of the type specified. which includes a tool housing having an opening or recess therein to accommodate an elongated magazine provided with a row of cartridgechambers, a barrel mounted in and slidable telescopically relative to the housing from an extended position, to a retracted position in which the tool is conditioned for firing, by urging the muzzle of the tool against a surface, the barrel being normally resiliently urged towards its fully extended position, and at its end remote from the muzzle of the tool, having a pair of arms adapted to slidably embrace the magazine, one arm being provided with a pawl co-operable with first cam surfaces of the magazine to bodily advance the magazine in a step-wide manner, generally transversely of the barrel, during retraction of the barrel relative to the housing, and the other arm being provided with a pawl cooperable with second cam surfaces of the magazine to bodily advance the magazine in a step-wise manner, gennerally transversely of the barrel, during extension of the barrel relative to the housing.

7. A tool as claimed in claim 6, wherein the pawls are so positioned that, in an intermediate position of the barrel they are both separated from their associated cam surfaces, enabling the magazine to be bodily moved transversely through the tool independently of the operating means.

8. A tool as claimed in claim 6, wherein at least one of the pawls is mounted for limited transverse movement relative to the axis of the barrel.

9. A tool as claimed in claim 6, wherein the pawls and cam surfaces are so arranged and dimensioned that the magazine is stepped by retraction of the barrel to a position in which a cartridge-receiving chamber is in operative alignment with a firing pin of the tool, whilst the magazine is stepped by extension of the barrel to a position in which no cartridge-receiving chamber is in operative alignment with the firing pin.

10. A tool as claimed in claim 6, wherein retraction of the barrel relative to the housing is adapted to cock the firing mechanism of the tool.

11. A tool as claimed in claim 10, wherein the arms, at their ends remote from the muzzle of the tool, engage and cock the firing mechanism upon retraction of the barrel.

12. A tool as claimed in claim 1, provided with a resiliently mounted breech block which, in the retracted position of the barrel, resiliently engages the magazine and urges it into sealing engagement with the barrel.

13. A tool as claimed in claim 1, wherein gas vents are provided in the bore of the barrel adjacent the muzzle of the tool.

14. A tool as claimed in claim 1, wherein co-operable means are associated with the magazine and barrel to index the cartridge-receiving chambers of the magazine in alignment with the bore of the barrel in the operative condition of the tool.

15. A tool as claimed in claim 14, wherein said means serve to effect a gas seal between the barrel bore and chambers.

16. A semi-automatic cartridge-operated hand tool for firing fasteners into surfaces, comprising a tool housing, a barrel mounted for longitudinal movement relative to the housing between a normal extended position, and a retracted position in which the tool is conditioned for firing, by urging the muzzle end of the tool against a surface into which a fastener is to be fired, the tool being adapted to slidably accommodate a generally elongated magazine provided with a row of cartridge-receiving chambers and with a plurality of generally longitudinally directed slots arranged side-by-side in a row and formed integrally with the magazine, the side surfaces of the slots constituting camming surfaces, operating means located Wholly within the housing and including a camming'pawl connected to the barrel for bodily longitudinal movement therewith, said camming pawl being adapted to longitudinally slidably co-operate with the camming surfaces of a magazine when operatively assembled to the tool, during movement of the barrel from its extended to its retracted position, to cam the magazine bodily, generally transversely through the housing along a linear path in a step-Wise manner, to bring successive cartridge-receiving chambers of an operatively assembled magazine into alignment with the barrel, the camming pawl being adapted to be wholly disengaged from the camming surfaces of the operatively assembled magazine over a region of the longitudinal path of travel of the camming pawl and barrel, to permit manual transverse displacement of the magazine through the housing independently of the operating means.

17. In a cartridge-operated hand tool of the type specified, a housing having an opening therein to accommodate an elongated magazine provided with a row of cartridge chambers and with a plurality of slots defining indexing surfaces, a barrel mounted in the housing and movable longitudinally relative to the housing from an extended position, to a retracted position, in which the tool is conditioned for firing, by urging the muzzle of the tool against a surface, operating means, disposed within the housing, including first and second operating members co-operable with the indexing surfaces of the slots of a magazine when operatively assembled to the tool, longitudinal movement of the barrel between said positions being transmitted to an operatively assembled magazine, to effect bodily step-wise advancing movement of the magazine generally transversely of the barrel through the housing, by longitudinal displacement of the operating means relative to the magazine Whilst engaging the indexing surfaces of the slots.

18. In combination: an elongated magazine provided with a row of cartridge chambers, the axes of which are disposed in a common transverse plane, and including upper and lower faces disposed on opposite sides of said common plane, each provided with a row of open-ended camming slots, the side walls of which comprise a repetitive series of camming surfaces extending in the general direction of the axes of the chambers; and a semi-automatic,

cartridge-operated hand tool including a housing having openings therein dimensioned to slidably accommodate the magazine and permit the passage thereof through the housing along a generally linear path transverse to the longitudinal axis of the housing, a barrel telescopically and longitudinally slidably mounted within the housing, having a muzzle end disposed externally of the housing and an opposite inner end located within the housing and connected to first and second arms slidably embracing said faces of the magazine, spring means operable normally to bias the barrel towards an extended position relative to the barrel, the barrel being manually displaceable to a retracted position, in which the tool is conditioned for firing, by urging the muzzle end of the barrel against a surface; operating means disposed wholly Within the housing, adapted to be bodily longitudinally displaced during movement of the barrel between its extended and retracted positions, said operating means including a rockable pawl, carried by and movable with the first arm, movable generally longitudinally in the plane of one of said faces of the magazine, said rockable pawl, in the extended position of the barrel, being longitudinally separated from the camming slots of one row thereof, said rockable pawl entering successive camming slots of said one row during movement of the barrel from its extended to its retracted position and cammingly engaging the side walls, but not the bottom thereof, to cam the magazine bodily step-wise transversely through the tool, said operating means further including a non-rockable pawl, movable generally longitudinally in the plane of the other of said faces of the magazine, said non-rockable pawl, during stepwise displacement of the magazine, being displaced longitudinally whilst cammingly engaging the side walls of successive camming slots of the other of said rows.

19. The combination according to claim 18, wherein the upper and lower faces of the magazine are each formed with a transversely extending shoulder, the two shoulders being directed in opposite longitudinal directions, the camming slots of the two rows being formed in, and opening through, the shoulders, and being flat-bottomed.

References Cited UNITED STATES PATENTS 2,930,041 3/ 1960 Massacrier 22711 3,048,850 8/1962 Schilling 22711 3,363,817 1/1968 Brack 2279 THERON E. CONDON, Primary Examiner H. M. CULVER, Assistant Examiner 

